Wedged hepatic venous pressure: A clinical evaluation

Abstract

The measurement of wedged hepatic venous pressure can be accomplished in approximately 90 per cent of patients and is without danger in experienced hands. From it a reliable estimate of portal vein pressure can be made. If inferior vena caval pressure is used as a zero reference point, non-cirrhotic ascites and right heart failure do not cause elevations of wedge pressure. Moderate and marked elevations are seen only in fibrotic liver disease, although mild elevations have been found in patients with no evidence of liver disease. In the earlier stages of cirrhosis wedge pressure may be normal, therefore in the lower pressure ranges neither the presence or absence of elevated wedge pressure can be considered diagnostic with respect to cirrhosis. The chief technical problem in wedge pressure measurement is that there is no safeguard in inexperienced hands against the recording of a falsely low pressure when the catheter is caught at a venous bifurcation and incompletely wedged. Therefore it is recommended that wedge pressure be recorded in at least two areas in the liver. There are rare instances (in our experience always in patients with complicated intra-abdominal circulatory problems) where wedge pressures may be difficult or impossible to interpret properly. Wedge pressure determination has proved to be of practical clinical value in several circumstances. It may establish a definite diagnosis of cirrhosis in problem cases in which liver biopsy is hazardous or technically not satisfactory. In patients with known cirrhosis who have had gastrointestinal bleeding from an unknown source it will provide important evidence in favor of or against construction of a portacaval shunt. It will differentiate reliably between intrahepatic and extrahepatic portal obstruction in patients with known esophageal varices.